Position adjustable steering device

ABSTRACT

When clamped side plates of an upper column bracket (movable bracket) are fastened via clamping side plates of an upper fixed bracket by a fastening shaft in response to a rotating operation of an operating lever, the brackets are locked with each other. A pressing mechanism that includes a pressing member moves in the axial direction of the fastening shaft in accordance with fastening by the fastening shaft, and presses a lower tube (inner tube) through an insertion hole formed in an upper tube (outer tube). The entirety of the axial force of the fastening shaft is used as a retaining force for retaining the posture of a steering column.

INCORPORATION BY REFERENCE

This application is a divisional application of U.S. patent applicationSer. No. 13/713,440, filed Dec. 13, 2012, which claims priority toJapanese Patent Applications No. 2011-279883 filed on Dec. 21, 2011 andNo. 2011-279884 filed on Dec. 21, 2011. The disclosures of the aboveapplications are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a position adjustable steering device.

2. Description of Related Art

There is a steering column device in which a vehicle body attachmentbracket is fastened to reduce the diameter of an outer column (outertube) with an axial slit via a pair of clamp members, thereby clampingan inner column (inner tube) to the outer column (see, for example,Japanese Patent No. 4609203, Japanese Patent Application Publication No.2010-105662 (JP 2010-105662 A), and Japanese Patent ApplicationPublication No. 2010-189003 (JP 2010-189003 A)).

There is a steering column device in which a fixed side wall of avehicle body fixed bracket (fixed bracket) is arranged at one side of atubular steering column, and a tension plate, which serves as an elasticmember and of which one end is fixed to a top plate of the fixedbracket, is arranged at the other side of the steering column (see, forexample, Japanese Patent Application Publication No. 2009-286341 (JP2009-286341 A)).

In JP 2009-286341 A, a side plate of a fastening bracket fixed to anouter column (outer tube) of the steering column is fastened toward thefixed side wall by a fastening member. In this way, the brackets arelocked. In addition, there is provided a coupling member that couplesthe tension plate to an inner column (inner tube). The coupling memberpasses through the outer column and the inner column, and a rib portionformed at one end of the coupling member is located inside the innercolumn. When the brackets are fastened by the fastening member, the ribportion of the coupling member pulled by the tension plate is pressedagainst the inner periphery of the inner column. As a result, the innercolumn is pressed against the outer column.

There is a steering device that prevents displacement in a telescopicdirection by pressing the outer periphery of an inner column. The outerperiphery of the inner column is pressed by pressing a column retainingmember with a slit, using a plate portion of a tilt bracket (fixedbracket) fixed to a vehicle body, thereby reducing the inside diameterof the column retaining member (see, for example, WO05/037627).

There is a vehicle steering device in which a lock plate fixed to anupper bracket (fixed bracket) and a lock plate fixed to a distancebracket (movable bracket), to which a column jacket is fixed,respectively have teeth that mesh with each other, and axial movement ofthe column jacket is prevented by the meshing of the teeth (see, forexample, Japanese Patent Application Publication No. 7-117685 (JP7-117685 A).

In Japanese Patent No. 4609203, JP 2010-105662 A and JP 2010-189003 A,the inner column is retained by reducing the diameter of the outercolumn (outer tube). Therefore, there is a possibility that sufficientretaining force will not be obtained due to the influence of, forexample, variations in dimensional accuracy.

In JP 2009-286341 A, the coupling member passes through the outer columnand the inner column, and the rib portion formed at one end of thecoupling member is located inside the inner column. Therefore, it isdifficult to assemble the steering column device.

In WO05/037627, the inner column is retained by reducing the diameter ofthe column retaining member. Therefore, there is a possibility thatsufficient retaining force will not be obtained due to the influence of,for example, variations in dimensional accuracy.

In JP 7-117685 A, the teeth of the both lock plates may be fastened toeach other to be locked in a state where top portions of the teeth faceeach other. In this case, when the both lock plates are displaced bysome impact and placed in a state where the teeth of one of the lockplates face tooth grooves of the other lock plate, the axial force of afastening shaft is reduced, and the retainment of the posture of thesteering column may be insufficient.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a position adjustablesteering device that reliably retains the posture of a steering columnand that is easily assembled.

An aspect of the invention relates to a position adjustable steeringdevice, including: a steering column that includes an outer tube and aninner tube that are fitted to each other so as to be relatively slidablein an axial direction of the steering column to make telescopicadjustment, and that support a steering shaft such that the steeringshaft is rotatable; a fixed bracket that has a pair of clamping sideplates, and that is fixed to a vehicle body; a movable bracket that hasa pair of clamped side plates arranged along inner side faces of therespective clamping side plates, and that is fixed to the outer tube; afastening mechanism that includes a fastening shaft that passes throughthe clamping side plates and the clamped side plates, and that achievestelescopic lock by fastening the clamped side plates with use of thefastening shaft via the clamping side plates in accordance with arotating operation of an operating lever; an insertion hole that isformed in the outer tube; and a pressing mechanism that moves in anaxial direction of the fastening shaft in accordance with fastening bythe fastening shaft, and that has a pressing member that presses theinner tube through the insertion hole.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments with reference to the accompanying drawings,wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a schematic view of a position adjustable steering deviceaccording to an embodiment of the invention, as viewed from the leftside of the position adjustable steering device;

FIG. 2 is a schematic view of the position adjustable steering deviceaccording to the embodiment of the invention, as viewed from the rightside of the position adjustable steering device;

FIG. 3 is a sectional view that is taken along the line III-III in FIG.1;

FIG. 4 is an enlarged sectional view of main portions of the positionadjustable steering device according to the embodiment of the invention,including a pressing mechanism before pressing;

FIG. 5 is an enlarged sectional view of the main portions of theposition adjustable steering device according to the embodiment of theinvention, including the pressing mechanism after pressing;

FIG. 6 is a sectional view that is taken along the line III-III in FIG.1 according to an alternative embodiment of the invention;

FIG. 7 is a perspective view of a pressing member shown in FIG. 6; and

FIG. 8 is a schematic view of a position adjustable steering deviceaccording to an alternative embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiment of the invention will be described withreference to the accompanying drawings. FIG. 1 and FIG. 2 are schematicviews that show the schematic configuration of a position adjustablesteering device according to an embodiment of the invention. FIG. 1 is aview of the position adjustable steering device 1 as viewed from theleft side of position adjustable steering device 1. FIG. 2 is a view ofthe position adjustable steering device 1 as viewed from the right sideof position adjustable steering device 1. As shown in FIG. 1, theposition adjustable steering device 1 includes a steering member 2, suchas a steering wheel, and a steering mechanism 3. The steering mechanism3 steers steered wheels (not shown) in response to a steering operationof the steering member 2. For example, a rack and pinion mechanism isused as the steering mechanism 3.

The steering member 2 and the steering mechanism 3 are mechanicallycoupled to each other via a steering shaft 4, an intermediate shaft 5,and the like. The rotation of the steering member 2 is transmitted tothe steering mechanism 3 via the steering shaft 4, the intermediateshaft 5, and the like. The rotation transmitted to the steeringmechanism 3 is converted to an axial movement of a rack shaft (notshown). In this way, the steered wheels are steered.

The steering shaft 4 includes a tubular upper shaft 6 and a tubularlower shaft 7. The upper shaft 6 and the lower shaft 7 are relativelyslidably fitted to each other through, for example, spline fitting orserration fitting. The steering member 2 is coupled to one end of theupper shaft 6. The steering shaft 4 is telescopic in its axial directionX1. The steering shaft 4 is passed through a tubular steering column 8,and is rotatably supported by the steering column 8 via a plurality ofbearings 9, 10.

The steering column 8 includes an upper tube 11 and a lower tube 12. Theupper tube 11 is an outer tube. The lower tube 12 is an inner tube. Theupper tube 11 and the lower tube 12 are fitted to each other so as to berelatively slidable in the axial direction. Thus, the steering column 8is telescopic in the axial direction, and telescopic adjustment(described later) is allowed. The upper tube 11 supports the upper shaft6 via the bearing 9 such that the upper shaft 6 is rotatable. The uppertube 11 is coupled to the upper shaft 6 via the bearing 9 so as to bemovable together with the upper shaft 6 in the axial direction X1 of thesteering shaft 4.

A lower column bracket 13 is fixed to the outer periphery of the lowertube 12. The lower column bracket 13 is pivotably supported by a lowerfixed bracket 15 via a tilt central shaft 16. The lower fixed bracket 15is fixed to a vehicle body 14. The steering column 8 and the steeringshaft 4 are pivotable about the tilt central shaft 16. By causing thesteering shaft 4 and the steering column 8 to pivot about the tiltcentral shaft 16, it is possible to adjust the position of the steeringmember 2 in the height direction (so-called tilt adjustment). Inaddition, by extending or contracting the steering shaft 4 and thesteering column 8 in the axial direction X1, it is possible to adjustthe position of the steering member 2 in the height direction and theposition of the steering member 2 in the axial direction (so-calledtelescopic adjustment).

The position adjustable steering device 1 includes a fastening mechanism17 used to achieve tilt lock and telescopic lock to fix the position ofthe steering member 2 of which the height has been adjusted.Specifically, an upper column bracket 18, which may function as amovable bracket, is fixed to the upper tube 11 (outer tube). The uppercolumn bracket 18 is coupled to an upper fixed bracket 19, which mayfunction as a fixed bracket and which is fixed to the vehicle body 14 bythe fastening mechanism 17. Thus, tilt lock and telescopic lock areachieved. As a result, the position of the steering column 8 is fixedwith respect to the vehicle body 14, and therefore the position of thesteering member 2 is fixed.

As shown in FIG. 1 and FIG. 2, the fastening mechanism 17 includes afastening shaft 20 and a cam mechanism 22. The fastening shaft 20 passesthrough a pair of clamping side plates 29, 30 of the upper fixed bracket19 and a pair of clamped side plates 26, 50 of the upper column bracket18. The cam mechanism 22 presses the clamping side plates 29, 30 againstthe clamped side plates 26, 50 in response to a rotating operation of anoperating lever 21 that is rotatable about an axis C1 of the fasteningshaft 20. The cam mechanism 22 is arranged along the clamping side plate29 that faces the clamped side plate 26.

FIG. 3 is a diagrammatic sectional view of the position adjustablesteering device 1, taken along the line III-III in FIG. 1. As shown inFIG. 3, the cam mechanism 22 includes a cam 23 and a cam follower 24.The rotation of the cam follower 24 is restricted by a vertically longhole 37 of the clamping side plate 29 of the upper fixed bracket 19. Thecam 23 is rotatable together with the operating lever 21. The cam 23 andthe cam follower 24 have cam protrusions (not shown) on their contactfaces.

In accordance with the relative rotation between the cam 23 and the camfollower 24, the cam 23 moves the cam follower 24 in an axial directionY1 of the fastening shaft 20. The cam 23 performs the function ofpressing the clamping side plate 29 (30) of the upper fixed bracket 19against the clamped side plate 26 (50) of the upper column bracket 18.Thus, the brackets 18, 19 are locked, and tilt lock and telescopic lockare achieved.

The upper column bracket 18, which may function as a movable bracket, isa groove-shaped member that opens upward. The upper column bracket 18includes the clamped side plates 26, 50 and a coupling plate 28. A firstend portion 261 of the clamped side plate 26 is fixed to the outerperiphery of the upper tube 11. Referring back to FIG. 2, the clampedside plate 50 facing the clamping side plate 30 includes a main portion51 and a pair of vertical plate portions 54, 55 that extend toward theupper tube 11, from a pair of end portions 52, 53 of the main portion 51in the longitudinal direction of the steering column 8. The main portion51 has a transversely long hole 36, through which the fastening shaft 20is passed, and extends along the longitudinal direction of the steeringcolumn 8 (which corresponds to the axial direction X1 of the steeringshaft 4). First end portions of the clamped side plate 50 (whichcorrespond to end portions 541, 551 of the vertical plate portions 54,55) are fixed to the outer periphery of the upper tube 11.

As shown in FIG. 3, the coupling plate 28 couples second end portions262, 502 of the clamped side plates 26, 50 to each other. The upperfixed bracket 19 is a groove-shaped member, as a whole, which opensdownward, and is formed so as to be bilaterally symmetric. That is, theupper fixed bracket 19 includes the clamping side plates 29, 30, acoupling plate 31 and a plate-like mounting stay 32. The clamping sideplates 29, 30 face each other in the lateral direction. The couplingplate 31 couples upper ends of the clamping side plates 29, 30 to eachother. The mounting stay 32 is fixed to the upper face of the couplingplate 31, and extends in the substantially lateral direction.

The clamped side plates 26, 50 of the upper column bracket 18 arearranged between the clamping side plates 29, 30 of the upper fixedbracket 19. The upper fixed bracket 19 is fixed to the vehicle body 14via a pair of mounting members 33 coupled to the mounting stay 32. Themounting members 33 each are coupled to the mounting stay 32 bysynthetic resin pins 34 that pass through the mounting stay 32 in theup-down direction. The synthetic resin pins 34 may break. The mountingmembers 33 are fixed to the vehicle body 14 with fixing bolts 35.

Outer side faces of the clamped side plates 26, 50 of the upper columnbracket 18 are arranged along inner side faces 29 a, 30 a of theclamping side plates 29, 30 of the upper fixed bracket 19, respectively.The transversely long holes 36 for telescopic adjustment are formed inthe clamped side plates 26, 50 of the upper column bracket 18. Thetransversely long holes 36 extend in a direction perpendicular to thesheet on which FIG. 3 is drawn (corresponding to the axial direction X1in FIG. 1). The vertically long hole 37 for tilt adjustment is formed ineach of the clamping side plates 29, 30 of the upper fixed bracket 19.

The fastening mechanism 17 includes the fastening shaft 20, a nut 38,the cam 23 and the cam follower 24. The fastening shaft 20 is passedthrough the vertically long holes 37 of the clamping side plates 29, 30of the upper fixed bracket 19 and the transversely long holes 36 of theclamped side plates 26, 50 of the upper column bracket 18. The nut 38 isscrewed to a threaded portion formed at one end portion of the fasteningshaft 20. The cam 23 and the cam follower 24 are fitted to an outerperipheral portion near the other end portion of the fastening shaft 20.The cam 23 and the cam follower 24 constitute the cam mechanism 22.

A head 201 is formed at the other end portion of the fastening shaft 20.The head 201 of the fastening shaft 20 and the cam 23 are coupled to theoperating lever 21 so as to be rotatable together with the operatinglever 21. The cam follower 24 has a first portion 241 and a secondportion 242. The first portion 241 of the cam follower 24 is arrangedalong an outer side face 29 b of the clamping side plate 29 of the upperfixed bracket 19. The second portion 242 of the cam follower 24 isfitted into the vertically long hole 37 of the clamping side plate 29 ofthe upper fixed bracket 19 and the transversely long hole 36 of theclamped side plate 26 of the upper column bracket 18 so as to be movablein the directions in which the long holes 37, 36 extend. By forming awidth across flat, or the like, at a portion at which the second portion242 is fitted in the vertically long hole 37 of the clamping side plate29, the rotation of the second portion 242 is restricted by thevertically long hole 37.

A first intervening member 41 and a second intervening member 42 areinterposed between the nut 38 screwed to one end portion of thefastening shaft 20 and the clamping side plate 30 of the upper fixedbracket 19. The first intervening member 41 has a first portion 412 anda second portion 411. The first portion 412 of the first interveningmember 41 is arranged along the outer side face 30 b of the clampingside plate 30 of the upper fixed bracket 19.

The second portion 411 of the first intervening member 41 is fitted inthe vertically long hole 37 of the clamping side plate 30 of the upperfixed bracket 19 and the transversely long hole 36 of the clamped sideplate 50 of the upper column bracket 18 so as to be movable in thedirections in which the long holes 37, 36 extend. By forming a widthacross flat, or the like, at a portion at which the second portion 411is fitted in the vertically long hole 37 of the clamping side plate 30,the rotation of the second portion 411 is restricted by the verticallylong hole 37.

The second intervening member 42 includes a thrust washer 43 and athrust needle roller bearing 44. The thrust washer 43 is interposedbetween the first portion 412 of the first intervening member 41 and thenut 38. The needle roller bearing 44 is interposed between the thrustwasher 43 and the first portion 412 of the first intervening member 41.Due to the function of the second intervening member 42 that includesthe needle roller bearing 44, the nut 38 is able to smoothly rotatetogether with the fastening shaft 20.

A feature of the present embodiment is that a pressing mechanism 60 isprovided. The pressing mechanism 60 presses an outer face 12 b of oneside portion 12 a of the lower tube 12 (inner tube) in a directionparallel to the fastening shaft 20 through an insertion hole 11 b of oneside portion 11 a of the upper tube 11 (outer tube) when the pressingmechanism 60 is pressed by the clamping side plate 30 at the time offastening by the fastening mechanism 17. As shown in FIG. 3 and FIG. 4that is an enlarged view, the pressing mechanism 60 is provided so as toproject from an outer face 11 c of the one side portion 11 a of theupper tube 11. The pressing mechanism 60 includes an auxiliary movablebracket 61 and a pressing member 62. The auxiliary movable bracket 61 isin contact with the inner side face 30 a of the clamping side plate 30and is elastically deformable. The pressing member 62 is fixed to theauxiliary movable bracket 61, and is able to press the outer face 12 bof the one side portion 12 a of the lower tube 12 through the insertionhole 11 b of the upper tube 11. The pressing member 62 may be a resinmember or may be a metal member made of, for example, sintered metal.

The auxiliary movable bracket 61 has a pressed side plate 63 and a pairof coupling portions 66, 67. The pressed side plate 63 is pressed by theinner side face 30 a of the clamping side plate 30 in accordance withfastening by the fastening mechanism 17. The coupling portions 66, 67couple end portions 64, 65 of the pressed side plate 63 to the outertube 11, respectively. Each of the coupling portions 66, 67 haselastically deformable bending portions 71 to 74 (see FIG. 4 and FIG.5). The pressing member 62 is fixed to the pressed side plate 63 of theauxiliary movable bracket 61, at a position between the end portions 64,65.

As shown in FIG. 2, the pressing mechanism 60 is arranged between thevertical plate portions 54, 55 of the clamped side plate 50 in thelongitudinal direction of the steering column 8 (the axial direction X1of the steering shaft 4). As shown in FIG. 4, each of the couplingportions 66, 67 has a first coupling plate 81, a second coupling plate82, a third coupling plate 83 and a fourth coupling plate 84. Each ofthe first coupling plates 81 is coupled to a corresponding one of theend portions 64, 65 of the pressed side plate 63 via the first bendingportion 71 so as to be tilted with respect to the pressed side plate 63.Each of the second coupling plates 82 is coupled to a corresponding oneof the first coupling plates 81 via the second bending portion 72 so asto be tilted with respect to the first coupling plate 81, and isparallel to the pressed side plate 63. Each of the third coupling plates83 is coupled to a corresponding one of the second coupling plates 82via the third bending portion 73 so as to be perpendicular to the secondcoupling plate 82. Each of the fourth coupling plates 84 is coupled to acorresponding one of the third coupling plates 83 via the fourth bendingportion 74 so as to be tilted with respect to the third coupling plate83. The fourth coupling plates 84 extend in the radial direction of theupper tube 11, and one ends of the fourth coupling plates 84 are fixedto the upper tube 11.

When the pressed side plate 63 is pressed by the inner side face 30 a ofthe clamping side plate 30 in accordance with fastening by the fasteningmechanism 17, the bending portions 71 to 74 bend, the coupling portions66, 67 are deflected, and parallel displacement of the pressed sideplate 63 occurs, as shown in FIG. 5. As a result, the pressed side plate63 presses the outer face 12 b of the one side portion 12 a of the lowertube 12 via the pressing member 62. The cross section of the lower tube12, in which the outer face 12 b of the one side portion 12 a is pressedby the pressing member 62, elastically deforms from a circular shapeshown in FIG. 4 to an oblong elliptical shape shown in FIG. 5.

According to the present embodiment, when the clamped side plates 26, 50of the upper column bracket 18 (movable bracket) are fastened via theclamping side plates 29, 30 of the upper fixed bracket 19 by thefastening shaft 20 in response to a rotating operation of the operatinglever 21, both of the brackets 18, 19 are locked with each other. Inaddition, the pressing mechanism 60 pressed by the clamping side plate30 of the upper fixed bracket 19 presses the outer face 12 b of the oneside portion 12 a of the lower tube 12 (inner tube) through theinsertion hole 11 b of the one side portion 11 a of the upper tube 11(outer tube), as shown in FIG. 5. As a result, the lower tube 12 ispressed against the upper tube 11 in a direction parallel to thefastening shaft 20, mainly, the outer face of the other side portion 12c of the lower tube 12 is pressed by the inner periphery of the uppertube 11, and both of the tubes 11, 12 are reliably locked.

It is possible to use the entirety of the axial force of the fasteningshaft 20 as a retaining force for retaining the posture of the steeringcolumn 8. Therefore, it is possible to increase the retaining force evenwhen the operating force of the operating lever 21 is substantially thesame as that in related art. Consequently, in the event of a secondarycollision of a vehicle, it is possible to suppress changes in theposture of the steering column 8 before the tubes 11, 12 contract.Accordingly, at the time of absorbing a shock, it is possible to performa desired shock absorbing function by appropriately contracting thetubes 11, 12.

Furthermore, because the pressing mechanism 60 is configured such thatthe lower tube 12 (inner tube) is pressed from the outer side, theposition adjustable steering device 1 is easier to assemble than aposition adjustable steering device that is configured such that part ofthe pressing member is arranged inside the inner tube as described in JP2009-286341 A. The cross section of the lower tube 12 in which the outerface 12 b of the one side portion 12 a is pressed by the pressingmechanism 60 elastically deforms into an oblong elliptical shape asshown in FIG. 5. Thus, it is possible to press a radially upper portion12 d and a radially lower portion 12 e of the lower tube 12 against theinner periphery of the upper tube 11. Therefore, it is possible tofurther increase the retaining force for retaining the posture of thesteering column 8 by improving coupling force for coupling the tubes 11,12 to each other.

In accordance with fastening by the fastening mechanism 17, theauxiliary movable bracket 61 provided so as to protrude from the outerface 11 c of the one side portion 11 a of the upper tube 11 elasticallydeforms by being pressed by the clamping side plate 30. As a result, thepressing member 62 fixed to the auxiliary movable bracket 61 presses theouter face 12 b of the one side portion 12 a of the lower tube 12through the insertion hole 11 b of the upper tube 11. Because thepressing member 62 is fixed to the auxiliary movable bracket 61, it ispossible to stably press the lower tube 12.

The pressed side plate 63 of the auxiliary movable bracket 61 is insurface contact with the inner side face 30 a of the clamping side plate30, and receives a fastening force of the fastening mechanism 17. Thus,it is possible to increase the coupling force for coupling the upperfixed bracket 19 to the upper column bracket 18 (movable bracket) andthe auxiliary movable bracket 61 to each other. The pressed side plate63 of the auxiliary movable bracket 61 is supported at both ends by theend portions 64 and 65, and the pressing member 62 is fixed to thepressed side plate 63, at a position between the end portions 64, 65. Asa result, the pressing member 62 is stably supported. In addition, thebending portions 71 to 74 of each of the coupling portions 66, 67adjacent to the end portions 64, 65 of the pressed side plate 63elastically deform. Thus, it is possible to appropriately displace thepressing member 62, which is fixed to the pressed side plate 63 at aposition between the end portions 64 and 65, in a direction parallel tothe fastening shaft 20.

Each of the coupling portions 66, 67 has a plurality of (four, in thepresent embodiment) bending portions 71 to 74. With this configuration,it is possible to ensure a sufficient deflection amount even in thecompact pressing mechanism 60. Therefore, it is possible to reliablypress the lower tube 12 via the pressing member 62. The clamped sideplate 50 that faces the clamping side plate 30 has the vertical plateportions 54, 55 that are apart from each other in the longitudinaldirection of the steering column 8 (the axial direction X1 of thesteering shaft 4), and the auxiliary movable bracket 61 is arrangedbetween the vertical plate portions 54, 55. Therefore, it is possible toachieve size reduction.

At least part of the location of the fastening shaft 20 overlaps withthe location of the pressing member 62 in the longitudinal direction ofthe steering column 8 (the axial direction X1 of the steering shaft 4).Thus, the fastening force of the fastening shaft 20 is efficientlyconverted into the pressing force of the pressing member 62. In thisway, it is possible to increase the coupling force for coupling thetubes 11, 12 to each other at the time of fastening by the fasteningmechanism 17. Note that the invention is not limited to the aboveembodiment. At least one bending portion should be formed in each of thecoupling portions 66, 67 of the auxiliary movable bracket 61 of thepressing mechanism 60. In the above-described embodiment, the nut 38,the fastening shaft 20 and the operating lever 21 are configured torotate together with each other. Alternatively, there may be employed aconfiguration in which the operating lever 21 is rotated withoutrotating the fastening shaft 20 and the nut 38.

FIG. 6 shows an alternative embodiment of the invention. FIG. 6 is adiagrammatic sectional view of the position adjustable steering device1, taken along the line III-III in FIG. 1, according to the presentembodiment. As shown in FIG. 6, the cam mechanism 22 of the fasteningmechanism 17 includes the cam 23 and the cam follower 24. The cam 23 isrotatable together with the operating lever 21. The rotation of the camfollower 24 is restricted by the vertically long hole 37 of the clampingside plate 29 of the upper fixed bracket 19. The cam 23 and the camfollower 24 have cam protrusions (not shown) on their contact faces.

In accordance with the relative rotation between the cam 23 and the camfollower 24, the cam 23 moves the cam follower 24 in the axialdirection. The cam 23 performs the function of pressing the clampingside plate 29 (30) of the upper fixed bracket 19 against the clampedside plate 26 (27) of the upper column bracket 18. Thus, the brackets18, 19 are locked, and tilt lock and telescopic lock are achieved.

A feature of the present embodiment is as follows. There are providedpressing members that are able to press the lower tube 12 (inner tube)through insertion holes of the upper tube 11 (outer tube) as thepressing members move in the axial direction Y1 of the fastening shaft20 at the time of fastening by the fastening mechanism 17. In this way,telescopic lock of the tubes 11, 12 is ensured. A first pressing member150 and a second pressing member 160 are provided as the pressingmembers. Each of the pressing members 150, 160 is fixed to the uppercolumn bracket 18 (movable bracket).

Specifically, the first pressing member 150 has a body portion 151 and apressing piece 152. The body portion 151 is fixed along the inner sideface 26 a of the clamped side plate 26 of the upper column bracket 18.The pressing piece 152 extends from the body portion 151 so as to betilted (obliquely upward) with respect to the body portion 151. As shownin FIG. 6 and FIG. 7, the body portion 151 has a web 153 and a pair offlanges 154, and forms a grooved shape. The web 153 extends parallel tothe clamped side plate 26. The flanges 154 are provided at respectiveends of the web 153. An end face 154 a of each flange 154 is fixed tothe inner side face 26 a of the clamped side plate 26 by welding orpressure welding. A transversely long hole 155 is formed in the web 153of the body portion 151. The transversely long hole 155 extends parallelto a telescopic direction (axial direction X1). A second portion 242(described later) of the cam follower 24 is passed through thetransversely long hole 155. The pressing piece 152 is formed of a longplate that is bent from an upper edge of the web 153 of the body portion151 and is long in a direction parallel to the telescopic direction(axial direction X1).

Referring back to FIG. 6, the second pressing member 160 and the firstpressing member 150 are formed of members having the same shape. Thatis, the first pressing member 150 and the second pressing member 160 arearranged in opposite orientations in the axial direction Y1 of thefastening shaft 20. The second pressing member 160 has a body portion161 and a pressing piece 162. The body portion 161 is fixed along aninner side face 27 a of the clamped side plate 27 of the upper columnbracket 18. The pressing piece 162 extends from the body portion 161 soas to be tilted (obliquely upward) with respect to the body portion 161.A transversely long hole 165 is formed in a web 163 of the body portion161. The second portion 411 of the first intervening member 41 is passedthrough the transversely long hole 165. An end face of each flange 164of the body portion 161 is fixed to the inner side face 27 a of theclamped side plate 27 by welding or pressure welding.

The pressing piece 152 of the first pressing member 150 is able to pressthe lower tube 12 through an insertion hole 111 a formed in the uppertube 11. The pressing piece 162 of the second pressing member 160 isable to press the lower tube 12 through an insertion hole 111 b formedin the upper tube 11. The pressing piece 152 of the first pressingmember 150 and the pressing piece 162 of the second pressing member 160are tilted in opposite directions with respect to a vertical plane P1.

In the present embodiment, a slit 111 c is formed in the upper tube 11at a position between the pressing pieces 152, 162. The slit 111 cextends in the axial direction X1 (direction perpendicular to the sheeton which FIG. 6 is drawn). However, the slit 111 c may be omitted. Atthe time of fastening by the fastening mechanism 17, the pressingmembers 150, 160 move so as to approach each other in the axialdirection Y1 of the fastening shaft 20. Thus, the pressing pieces 152,162 of the pressing members 150, 160 cooperatively push the lower tube12 upward. As a result, the upper end of the outer periphery of thelower tube 12 is pressed against the inner periphery of the upper tube11, and the tubes 11, 12 are locked in the telescopic direction (axialdirection X1).

The upper column bracket 18, which may function as a movable bracket, isa groove-shaped member that opens upward, and is formed so as to bebilaterally symmetric. The upper column bracket 18 has the clamped sideplates 26, 27 and the coupling plate 28. First end portions 261, 271 ofthe respective clamped side plates 26, 27 are fixed to the outerperiphery of the upper tube 11. The coupling plate 28 couples second endportions 262, 272 of the clamped side plates 26, 27. That is, the secondend portions 262, 272 of the clamped side plates 26, 27 are coupled toend portions 281, 282 of the coupling plate 28, respectively.

A flexible portion 28 a is formed in a middle portion of the couplingplate 28. The flexible portion 28 a is elastically deformable such thata distance D1 between the clamped side plates 26, 27 is reduced. Theflexible portion 28 a may be an inverted V-shaped portion as shown inFIG. 6 or may be a wavy portion (not shown). The upper fixed bracket 19is, as a whole, a groove-shaped member that opens downward, and isformed so as to be bilaterally symmetric. That is, the upper fixedbracket 19 has the clamping side plates 29, 30, the coupling plate 31and the plate-like mounting stay 32. The clamping side plates 29, 30face each other in the lateral direction. The coupling plate 31 couplesupper ends of the clamping side plates 29, 30. The mounting stay 32 isfixed to the upper face of the coupling plate 31, and extends in thesubstantially lateral direction.

The clamped side plates 26, 27 of the upper column bracket 18 arearranged between the clamping side plates 29, 30 of the upper fixedbracket 19. The upper fixed bracket 19 is fixed to the vehicle body 14via the mounting members 33 coupled to the mounting stay 32. Themounting members 33 each are coupled to the mounting stay 32 with thesynthetic resin pins 34 that pass through the mounting stay 32 in theup-down direction. The synthetic resin pins 34 may break. The mountingmembers 33 each are fixed to the vehicle body 14 with the fixing bolt35.

The outer side faces of the corresponding clamped side plates 26, 27 ofthe upper column bracket 18 are arranged along inner side faces 29 a, 30a of the clamping side plates 29, 30 of the upper fixed bracket 19. Thetransversely long holes 36 for telescopic adjustment are formed in theclamped side plates 26, 27 of the upper column bracket 18. Thetransversely long holes 36 extend in a direction perpendicular to thesheet on which FIG. 6 is drawn (corresponding to the axial direction X1in FIG. 1). The vertically long hole 37 for tilt adjustment is formed ineach of the clamping side plates 29, 30 of the upper fixed bracket 19.

The fastening mechanism 17 includes the fastening shaft 20, a nut 38,the cam 23 and the cam follower 24. The fastening shaft 20 is passedthrough the vertically long holes 37 of the clamping side plates 29, 30of the upper fixed bracket 19 and the transversely long holes 36 of theclamped side plates 26, 27 of the upper column bracket 18. The nut 38 isscrewed to a threaded portion formed at one end portion of the fasteningshaft 20. The cam 23 and the cam follower 24 are fitted to an outerperipheral portion near the other end portion of the fastening shaft 20.The cam 23 and the cam follower 24 constitute the cam mechanism 22.

The head 201 is formed at the other end portion of the fastening shaft20. The head 201 of the fastening shaft 20 and the cam 23 are coupled tothe operating lever 21 so as to be rotatable together with the operatinglever 21. That is, by operating the operating lever 21, the pressingmembers 150, 160 push up the lower tube 12 (inner tube) with the use ofthe pressing pieces 152, 162. Thus, the lower tube 12 is radiallypressed against the upper tube 11 (outer tube), and a backlash of thelower tube 12 in the radial direction with respect to the upper tube 11is suppressed.

The cam follower 24 has the first portion 241 and the second portion242. The first portion 241 of the cam follower 24 is arranged along theouter side face 29 b of the clamping side plate 29 of the upper fixedbracket 19. The second portion 242 of the cam follower 24 is fitted intothe vertically long hole 37 of the clamping side plate 29 of the upperfixed bracket 19 and the transversely long hole 36 of the clamped sideplate 26 of the upper column bracket 18 so as to be movable in thedirections in which the long holes 37, 36 extend. By forming a widthacross flat, or the like, at a portion at which the second portion 242is fitted in the vertically long hole 37 of the clamping side plate 29,the rotation of the second portion 242 is restricted by the verticallylong hole 37.

The first intervening member 41 and the second intervening member 42 areinterposed between the nut 38 screwed to one end portion of thefastening shaft 20 and the clamping side plate 30 of the upper fixedbracket 19. The first intervening member 41 has the first portion 412and the second portion 411. The first portion 412 of the firstintervening member 41 is arranged along the outer side face 30 b of theclamping side plate 30 of the upper fixed bracket 19.

The second portion 411 of the first intervening member 41 is fitted inthe vertically long hole 37 of the clamping side plate 30 of the upperfixed bracket 19 and the transversely long hole 36 of the clamped sideplate 27 of the upper column bracket 18 so as to be movable in thedirections in which the long holes 37, 36 extend. By forming a widthacross flat, or the like, at a portion at which the second portion 411is fitted in the vertically long hole 37 of the clamping side plate 30,the rotation of the second portion 411 is restricted by the verticallylong hole 37.

The second intervening member 42 includes the thrust washer 43 and thethrust needle roller bearing 44. The thrust washer 43 is interposedbetween the first portion 412 of the first intervening member 41 and thenut 38. The needle roller bearing 44 is interposed between the thrustwasher 43 and the first portion 412 of the first intervening member 41.Due to the function of the second intervening member 42 that includesthe needle roller bearing 44, the nut 38 is able to smoothly rotatetogether with the fastening shaft 20.

According to the present embodiment, the clamped side plates 26, 27 ofthe upper column bracket 18 are fastened via the clamping side plates29, 30 of the upper fixed bracket 19 by the fastening shaft 20 inresponse of a rotating operation of the operating lever 21. Thus, bothof the brackets 18, 19 are locked. In addition, at the time of fasteningby the fastening shaft 20, the distance D1 between the clamped sideplates 26, 27 of the upper column bracket 18 is reduced. Accordingly,the pressing members 150, 160 move in the axial direction Y1 of thefastening shaft 20, and the pressing pieces 152, 162 of the pressingmembers 150, 160 press the lower tube 12 (inner tube) through theinsertion holes 111 a, 111 b of the upper tube 11 (outer tube),respectively. As a result, the lower tube 12 is pushed against the uppertube 11, and the tubes 11, 12 are reliably locked.

It is possible to use the entirety of the axial force of the fasteningshaft 20 as a retaining force for retaining the posture of the steeringcolumn 8. Therefore, it is possible to increase the retaining force evenwhen the operating force of the operating lever 21 is substantially thesame as that in related art. Consequently, in the event of a secondarycollision of a vehicle, it is possible to suppress changes in theposture of the steering column 8 before the tubes 11, 12 contract.Accordingly, at the time of absorbing a shock, it is possible to performa desired shock absorbing function by appropriately contracting thetubes 11, 12.

The pressing pieces 152, 162 of the pressing members 150, 160 are tiltedin opposite directions with respect to the vertical plane P1. Therefore,at the time of fastening by the fastening mechanism 17, the pressingpieces 152, 162, for example, cooperatively push up the lower tube 12 topress the lower tube 12 against the upper tube 11. In this way, it ispossible to stably retain the posture of the steering column 8. Inaddition, at the time of fastening by the fastening mechanism 17, theflexible portion 28 a of the coupling plate 28 that couples the clampedside plates 26, 27 of the upper column bracket 18 to each otherelastically deforms. In this way, the distance D1 between the clampedside plates 26, 27 is reduced. Thus, it is possible to reliably placethe tubes 11, 12 in the locked state by ensuring sufficientdisplacements of the pressing members 150, 160 in the axial direction ofthe fastening shaft 20.

In related art in which the lower tube is pushed up by the cam providedon the outer periphery of the sleeve that rotates together with thefastening shaft, an region of the lower tube in the axial direction,which the cam contacts, is short. In contrast to this, in the presentembodiment in which the pressing members 150, 160 are moved in the axialdirection Y1 of the fastening shaft 20, it is possible to extend theregion of the lower tube 11 in the axial direction X1, which thepressing piece 152 contacts, by extending the pressing piece 152 in theaxial direction X1 of the lower tube 12. In terms of this point as well,it is possible to reliably place the tubes 11, 12 in the locked state.Note that, in the present embodiment, the slit 111 c of the upper tube11 may be omitted.

Next, FIG. 8 shows an alternative embodiment of the invention. As shownin FIG. 8, the present embodiment mainly differs from the embodimentshown in FIG. 6 in the following point. In the embodiment shown in FIG.6, the single upper column bracket 18 is used as the movable bracket;whereas, in the present embodiment, a first upper column bracket 18P(first movable bracket) and a second upper column bracket 18Q (secondmovable bracket) are provided as the movable brackets.

The first upper column bracket 18P has a first side plate 171, a secondside plate 172 and a coupling plate 173. The first side plate 171 is aclamped side plate that is arranged along the inner side face 29 a ofthe clamping side plate 29 of the upper fixed bracket 19. The secondside plate 172 faces the inner side face of the first side plate 171.The coupling plate 173 couples the first side plate 171 and the secondside plate 172 to each other. The first side plate 171 has a first endportion 711 and a second end portion 712, and the second side plate 172has a first end portion 721 and a second end portion 722. The first endportions 711, 721 are fixed to the upper tube 11. The second endportions 712, 7122 are coupled to end portions 731, 732 of the couplingplate 173, respectively. The first pressing member 150 is fixed to theinner side face of the first side plate 171 that may function as aclamped side plate.

The second upper column bracket 18Q has a first side plate 181, a secondside plate 182 and a coupling plate 183. The first side plate 181 is aclamped side plate that is arranged along the inner side face 30 a ofthe clamping side plate 30 of the upper fixed bracket 19. The secondside plate 182 faces the inner side face of the first side plate 181.The coupling plate 183 couples the first side plate 181 and the secondside plate 182 to each other. The first side plate 181 has a first endportion 811 and a second end portion 812, and the second side plate 182has a first end portion 821 and a second end portion 822. The first endportions 811, 821 are fixed to the outer periphery of the upper tube 11.The second end portions 812, 822 are coupled to end portions 831, 832 ofthe coupling plate 183, respectively. The second pressing member 160 isfixed to the inner side face of the first side plate 181 that mayfunction as a clamped side plate.

The slit 111 c is formed in the upper tube 11. The slit 111 c extends inthe axial direction X1. The first end portions 711, 721 of the firstside plate 171 and second side plate 172 of the first upper columnbracket 18P and the first end portions 811, 821 of the first side plate181 and second side plate 182 of the second upper column bracket 18Q arefixed to the outer periphery of the upper tube 11 on respective sides ofthe slit 111 c.

Among the components in the embodiment shown in FIG. 8, the samecomponents as those in the embodiment shown in FIG. 6 are denoted by thesame reference numerals as those in FIG. 6. According to the presentembodiment, each of the first upper column bracket 18P and the secondupper column bracket 18Q, which may function as a movable brackets, isfixed to the upper tube 11 at two portions. Specifically, the firstupper column bracket 18P is fixed to the upper tube 11 at two portions,that is, the first end portion 711 of the first side plate 171 and thefirst end portion 721 of the second side plate 172. The second uppercolumn bracket 18Q is fixed to the upper tube 11 at two portions, thatis, the first end portion 811 of the first side plate 181 and the firstend portion 821 of the second side plate 182. Thus, it is possible tosuppress concentration of stress at each of the points of couplingbetween the first upper column bracket 18P and the second upper columnbracket 18Q, and the upper tube 11.

At the time of fastening by the fastening mechanism 17, the diameter ofthe upper tube 11 with the slit 111 c is reduced. Therefore, it ispossible to bring the upper column brackets 18P, 18Q, which are arrangedon respective sides of the slit 111 c, close to each other in the axialdirection Y1 of the fastening shaft 20. As a result, it is possible toreliably place the tubes 11, 12 in the locked state by ensuringsufficient displacements of the pressing members 150, 160 in the axialdirection Y1 of the fastening shaft 20.

In the above-described embodiment, the nut 38, the fastening shaft 20and the operating lever 21 are configured to rotate together with eachother. Alternatively, there may be employed a configuration in which theoperating lever 21 is rotated without rotating the fastening shaft 20and the nut 38. The invention is not limited to the above-describedembodiments, and various modifications may be made within the scope ofthe appended claims.

What is claimed is:
 1. A position adjustable steering device,comprising: a steering column that includes an outer tube and an innertube that are fitted to each other so as to be relatively slidable in anaxial direction of the steering column to make telescopic adjustment,and that support a steering shaft such that the steering shaft isrotatable; a fixed bracket that has a pair of clamping side plates, andthat is fixed to a vehicle body; a movable bracket that has a pair ofclamped side plates arranged along inner side faces of the respectiveclamping side plates, and that is fixed to the outer tube; a fasteningmechanism that includes a fastening shaft that passes through theclamping side plates and the clamped side plates, and that achievestelescopic lock by fastening the clamped side plates with use of thefastening shaft via the clamping side plates in accordance with arotating operation of an operating lever; an insertion hole that isformed in the outer tube; and a pressing mechanism that moves in anaxial direction of the fastening shaft in accordance with fastening bythe fastening shaft, and that has a pressing member that presses theinner tube through the insertion hole, wherein: a plurality of theinsertion holes are formed in a lower side portion of the outer tube,the pressing mechanism has a first pressing member and a second pressingmember each of which has a body portion fixed to the movable bracket anda pressing piece extending from the body portion, and which are fixed tothe respective clamped side plates, the pressing piece of the firstpressing member and the pressing piece of the second pressing member aretilted in opposite directions with respect to a vertical plane, and thepressing mechanism is configured such that the pressing pieces of thepressing members press the inner tube through the insertion holes indirections that are tilted with respect to the fastening shaft inaccordance with fastening by the fastening mechanism.
 2. The positionadjustable steering device according to claim 1, wherein: the movablebracket includes a coupling plate that couples the clamped side platesto each other; each of the clamped side plates has a first end portionfixed to the outer tube and a second end portion coupled to acorresponding one of end portions of the coupling plate; and thecoupling plate has a flexible portion that is elastically deformablesuch that a distance between the clamped side plates is reduced.
 3. Theposition adjustable steering device according to claim 2, wherein: afirst movable bracket and a second movable bracket are provided as themovable bracket; each of the first movable bracket and the secondmovable bracket has a first side plate that serves as the clamped sideplate arranged along a corresponding one of the clamping side plates ofthe fixed bracket, a second side plate that faces the first side plate,and a coupling plate that couples the first side plate and the secondside plate to each other; each of the first side plate and the secondside plate has a first end portion fixed to the outer tube and a secondend portion coupled to a corresponding one of end portions of thecoupling plate; a slit extending in an axial direction of the outer tubeis formed in the outer tube; and the first end portions of the firstside plate and the second side plate of the first movable bracket, andthe first end portions of the first side plate and the second side plateof the second movable bracket are fixed to the outer tube on respectivesides of the slit.